Thermal performance of earth-air heat exchanger for reducing cooling energy demand of office buildings in the United Kingdom

There is a rising demand for conventional mechanical cooling systems in UK buildings over the last 10 years, which is due to increase in building internal and solar heat gains. Use of passive and low energy strategies for cooling and heating of buildings is an attractive alternative for providing comfortable indoor environments with low energy use. Earth-air heat exchanger (EAHX) is a low-energy system that utilises the stable subsurface soil temperature to reduce ventilation air temperature. There appears to be very limited research and published data on their thermal performance in the UK. This paper evaluates the thermal performance of the earth-air heat exchanger under different configurations and operating conditions in the UK. Transient Systems Simulation Software (TRNSYS) has been used to model EAHX using UK climatic and soil parameters. The result reveals significant improvement in indoor thermal conditions and the potential to reduce use of energy intensive conventional cooling systems.